In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning.

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Permutation tests for large sequences

I would like to perform a permutation test on a particularly large data set, i.e. around 4 million entries. Basically, I need to get some number of random permutations of this data set. Usual way to ...
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1answer
90 views

How to define the motion path of one object on a surface of the other one?

I have an uncommon problem. There are 2 3D objects, which are represented by arrays of vertices and triangles (.stl files). Each of them contains a big enough amount of vertices: 1-10 mln ones. The ...
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1answer
145 views

Programming a promotions engine [closed]

I am trying to implement a promotions engine for an e-commerce application and I want to figure out how such engines work especially in situations like the following. Buy X Items from Category A ...
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2answers
196 views

Sequentially/parallel algorithm for extracting blob outer perimeter/contour length

I have labelled the connected components in a binary image and found their areas and bounding boxes. The components are not necessarily filled, and may contain holes. I wish to identify the component ...
8
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1answer
2k views

I know JavaScript really well, but i bomb coding interviews [closed]

So I'm currently on a hunt for a new position as a Front-End Developer. I know JavaScript very well and can wax poetically about Closures, Currying, Prototypal Inheritance, Design Patterns, App ...
3
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2answers
87 views

An algorithm for finding subset matching criteria?

I recently came up with a problem which I would like to share some thoughts about with someone on this forum. This relates to finding a subset. In reality it is more complicated, but I tried to ...
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2answers
287 views

Which algorithm is faster? [closed]

I'm creating a small game, where the computer generate pseudo random number in give range, and the user have to guess it. I also made the option to play computer vs computer. I mean the computer ...
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2answers
89 views

Algorithm to reverse engineer permutation [closed]

I have a sequence of permutations formed using these strings: "A", "BC" and "D". The permutations are: BCAD ABCD BCDA DABC ADBC DBCA Now I need to reverse engineer this; i.e. I have a text file ...
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1answer
191 views

How to create an algorithm for determining Boolean Tautologies

So i am right now exploring some topics in a proof course and it occurred to me to try to create a boolean tautology solver. I would like an algorithm that is more efficient than brute force. Problem ...
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0answers
124 views

Dynamic programming in Bin packing

Problem: Given a list L of objects of possible sizes from set S={1,2,4,8} and unlimited supply of bins of sizes 16 each and we have to use minimum possible numbers of bins to pack all objects of L. I ...
10
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5answers
758 views

Print the next smallest from 2^i * 5^j where i,j >= 0

I was asked this question during a technical phone screening recently and didn't do well. The question is included verbatim below. Generate {2^i * 5^j | i,j >= 0} sorted collection. ...
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2answers
264 views

What's the shortest generating one-way hash algorithm?

I have a 24 character long id which is guaranteed to be unique. I would like to shorten that to 7-10 (or even shorter) characters long. If I generate an short id randomly then I would have to check ...
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2answers
250 views

Algorithm for rating books: Relative perception [closed]

So I am developing this application for rating books (think like IMDB for books) using relational database. Problem statement : Let's say book "A" deserves 8.5 in absolute sense. In case if A is ...
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0answers
156 views

Dividing 2D grid to most efficient search

Requirements I have Grid of unlimited size (I don't and can't know what its size) There is Object that should be placed on the grid, every object have hes stream distance (in other words: range, ...
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1answer
90 views

Ensuring submitted hiscores are not fake

I have a small game that I would like to keep track og global hiscores for. The basic is simple: username and score is submitted to a server for storage and later polling. However how do I ensure that ...
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1answer
73 views

Decrease probability of picking a list's item based on its index

I have a list of sounds that are to be played when the user presses a button. For now I just generate a random number within the range of the list and just pick the sound with that index. (I also ...
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1answer
179 views

Traverse a matrix using a linear index to get an evenly distributed values sample

I'm looking for an algorithm idea on how to traverse a matrix using a linear index while avoiding row/column based traversals to get a more diverse distribution of values. To understand this better, ...
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0answers
131 views

GSP Algorithm explanation

I've been trying to implement the GSC algorithm in C++, however I need help with clarifying the definition: http://en.wikipedia.org/wiki/GSP_Algorithm GSP Algorithm makes multiple database ...
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1answer
58 views

Weight based mapping algorithm

I am writing automatic assignment of tasks to the users. Every user has a weight (integer) and tasks should be distributed to the users according to their weights. For example I have 10 tasks and User ...
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3answers
230 views

Given known inputs and outputs, can we generate candidate functions that will map the inputs to outputs? [closed]

I've run into a problem where I have a set of inputs, as well as a couple known input-output pairs. I am interested in the output, but in order to get that, I need to figure out how the input is used ...
3
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1answer
134 views

Identify algorithm for my resource allocation needs

I'm trying to automate a task and I lack the right vocabulary to look up the correct algorithm. It really feels like a common problem that has likely been solved many times before. All I'm looking ...
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1answer
47 views

Equidistant polygons

Consider these polygons: For reasons of simplicity I only consider triangles or polygons with 4 vertices. These shapes are specified by the vertices, the output of the program should be modified ...
4
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3answers
790 views

What is a helper? Is it a design pattern? Is it an algorithm? [closed]

Maybe a little tongue-in-cheek, but as I can't find this answer anywhere through Google, so to ensure Programmers Stackexchange has the answer: What is a helper? I see the name being used everywhere ...
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0answers
70 views

Can sequence alignment algorithms be used for search implementation?

Hi I want to implement a search on a website which includes imperfect search results. Meaning, if the search term is misspelled or slightly different from a 100% match, the function should still ...
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1answer
190 views

Calculate reachability of one point from another

I have an array which stores a set of positive x coordinates in sorted way, say arr={1, 4, 5, 9, 12, 45} etc. And I have a maximum distance k which I can go from one point to another point let ...
8
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1answer
135 views

An algorithm for reconstructing a graph from its shortest path information?

I have some shortest path data for a graph. Can I reconstruct the graph itself from this data? More precisely, I have a boolean (0/1) matrix for each vertex v in graph (V, E). Matrix element [s,d] is ...
3
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1answer
99 views

Does parallel mergesort run differently on mesh vs linear array of processors?

I'm currently taking course on introduction to algorithm and I came across the parallel mergesort algorithm. My question is: Is there any differences in the algorithm plan if it runs on a 2d mesh ...
4
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2answers
282 views

Which algorithms do I need to look into?

First things first: I need to apologize in advance about the bad choice of title for this question, but I really couldn't come up with something meaningful. I'm actually looking for suggestions as to ...
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3answers
202 views

An algorithm for finding converse duplicates of ordered pairs

Given an array of ordered pairs of values, is there a well-known algorithm to find converse duplicates? [Converse meaning the same values, but in the opposite order.] That is, given ...
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2answers
230 views

Reduce a list of IPv4 to lowest common CIDR

I have a long list of IP addresses that show some pattern of closeness Example: XX.249.91.16 XX.249.91.21 XX.249.91.32 XX.249.91.160 XX.249.91.165 XX.249.92.15 XX.249.92.25 ...
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votes
1answer
300 views

get all the combination of a given set of numbers [duplicate]

I m trying to get the possible combinations of a given set of numbers say for example 123 The possible combinations would be 123 132 213 231 312 321 For this i have written a code as below - ...
11
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5answers
924 views

Algorithm for percentage without knowing total number

Suppose there are n lines for a hotline. Whenever a customer calls the hotline, the call is forwarded to one of the n lines. And I want to assign percentage of calling to each of the n lines. ...
0
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1answer
470 views

Is Microsoft Solver capable of solving such complex scheduling problems

I'm writing a application that will decide the scheduling plan for a few dozen people according to their occupation (role) and availability (week day and hours). I've used a excel spreadsheet to help ...
3
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2answers
82 views

Trivially Sortable Encoding for Arbitrary-Precision Decimals

I'm looking for a reasonably(*) space-efficient way to encode arbitrary-precision decimals (e.g. BigDecimal), such that when sorting the bit-pattern of the encodings lexicographically, the numbers ...
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0answers
40 views

Generating all the words accepted by a deterministic finite automaton [duplicate]

Imagine you've got a finite deterministic automaton A defining some finite regular language L, consisting of N words. The first question is: how would you determine the number of words N? Then, I ...
3
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1answer
104 views

Defining a random “safe” path for a game character

I am writing a game in Java and it can be likened to the recently popular game "Flappy Bird" in the sense that the character moves up and down and the users touch and must avoid the obstacles. The ...
0
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1answer
308 views

problem on calculating Big O complexity

i have this function on which i have to calculate the time complexity with the Big O notation: public void print(ArrayList<String> operations, ArrayList<LinkedHashSet<String>> ...
2
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1answer
113 views

Random forest ML algorithm suitable for use on cluster based HPC?

I need help in identifying a better algorithm. I have developed a script using pythons scipy package to analyse a rather large model that I wish to solve. The model contains over 12GB of data ...
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2answers
65 views

Adding a minimum rectangle overlap threshold

I have a function that works perfectly for detecting whether or not r1 overlaps with r2: boolean overlaps( Rectangle r1, Rectangle r2 ) { return r1.x < r2.x + r2.width && r1.x + ...
0
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1answer
46 views

Matching weighted unbalanced Bipartite graph

I am looking for a way to solve an assignment problem, but I am having some problems finding the correct algorithm to use. I have 2 list of nodes A and B, and in my problem may the length of A not be ...
0
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1answer
113 views

How to create a scoring system with time and correct answers for a game?

o create a scoring system with time and correct answers for a game? up vote 0 down vote favorite I have a small mobile quiz game, which consists of 30 questions, and a timer which starts from 0 ...
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3answers
74 views

Algorithm to reduce calls to mapping API

A random distribution of points lies on a map. This data lies behind an API, and I want to grab the complete set of points within a given bounding box. I can query the API with the bounding box and ...
2
votes
3answers
181 views

Count unique visitors by group of visited places

I'm facing the problem of counting the unique visitors of groups of places. Here is the situation: I have visitors that can visit places. For example, that can be internet users visiting web pages, ...
0
votes
1answer
328 views

Algorithm to Copy data faster than windows default copy provider

I need an algorithm which can copy data(files/folder) from one place to another, faster than windows default copy/paste option. I'm working in vc++. Is there any algorithm by which I can do copy/paste ...
0
votes
1answer
214 views

How can I rank teams based off of head to head wins/losses

I'm trying to write an algorithm (specifically in Ruby) that will rank teams based on their record against each other. If a team A and team B have won the same amount of games against each other, then ...
0
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1answer
64 views

Algorithm to measure how “diffused” 5,000 pennies are in an economy?

Please allow me to use this example/metaphor to describe an algorithm I need. Objects There are 5 thousand pennies. There are 50 cups. There is a tracking history (Passport "stamp" etc) that is ...
3
votes
4answers
252 views

Indefinite loops where the first time is different

This isn't a serious problem or anything someone has asked me to do, just a seemingly simple thing that I came up with as a mental exercise but has stumped me and which I feel that I should know the ...
0
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0answers
447 views

Multidimensional multiple-choice knapsack problem: find a feasible solution

My assignment is to use local search heuristics to solve the Multidimensional multiple-choice knapsack problem, but to do so I first need to find a feasible solution to start with. Here is an example ...
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1answer
136 views

How to solve linear recurrences involving two functions?

Actually I came across a question in Dynamic Programming where we need to find the number of ways to tile a 2 X N area with tiles of given dimensions.. Here is the problem statement Now after a bit ...
3
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2answers
199 views

Find points whose pairwise distances approximate a given distance matrix

Problem. I have a symmetric distance matrix with entries between zero and one, like this one: D = ( 0.0 0.4 0.0 0.5 ) ( 0.4 0.0 0.2 1.0 ) ( 0.0 0.2 0.0 0.7 ) ( 0.5 1.0 0.7 0.0 ) I would ...